Some vehicular headlamps include a cooling fan to dissipate heat. A so-called forced cooling method using a cooling fan has an excellent heat dissipating performance so as to reduce a size of a heat sink, which may contribute to reducing a size of a vehicular headlamp.
Japanese Patent Laid-Open No. 2013-54919 discloses a technology which controls a cooling fan depending on environmental temperature in a vehicular lamp including a cooling fan.
Further, there is a vehicular headlamp including a cooling fan is provided with a power converting unit which obtains an output current to turn on a light source and a control unit which converts a current value of the output current to adjust an amount of luminescence of a light source.